From 9a1c801a1a3c102bf95c5339c9e985b26b823a21 Mon Sep 17 00:00:00 2001 From: Stephen Gallagher Date: Tue, 6 Jan 2026 14:19:30 -0500 Subject: [PATCH] Fix discarded const qualifiers It's unsafe to implicitly discard the const qualifier on a pointer. In overlay_fixup_phandle(), this was probably just an oversight, and making the "sep" variable a const char * is sufficient to fix it. In create_node(), however, the "p" variable is directly modifying the buffer pointed to by "const char* node_name". To fix this, we need to actually make a duplicate of the buffer and operate on that instead. This introduces a malloc()/free() and an unbounded strdup() into the operation, but fdtput isn't a long-running service and the node_name argument comes directly from argv, so this shouldn't introduce a significant performance impact. Signed-off-by: Stephen Gallagher Signed-off-by: David Gibson --- fdtput.c | 8 +++++--- libfdt/fdt_overlay.c | 3 ++- meson.build | 1 + 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/fdtput.c b/fdtput.c index 05f2b93..fdb581a 100644 --- a/fdtput.c +++ b/fdtput.c @@ -254,19 +254,21 @@ static int create_paths(char **blob, const char *in_path) static int create_node(char **blob, const char *node_name) { int node = 0; - char *p; + const char *p; + char *path = NULL; p = strrchr(node_name, '/'); if (!p) { report_error(node_name, -1, -FDT_ERR_BADPATH); return -1; } - *p = '\0'; *blob = realloc_node(*blob, p + 1); if (p > node_name) { - node = fdt_path_offset(*blob, node_name); + path = xstrndup(node_name, (size_t)(p - node_name)); + node = fdt_path_offset(*blob, path); + free(path); if (node < 0) { report_error(node_name, -1, node); return -1; diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c index e6b9eb6..51a3859 100644 --- a/libfdt/fdt_overlay.c +++ b/libfdt/fdt_overlay.c @@ -407,7 +407,8 @@ static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, const char *fixup_str = value; uint32_t path_len, name_len; uint32_t fixup_len; - char *sep, *endptr; + const char *sep; + char *endptr; int poffset, ret; fixup_end = memchr(value, '\0', len); diff --git a/meson.build b/meson.build index 66b44e8..501b706 100644 --- a/meson.build +++ b/meson.build @@ -18,6 +18,7 @@ add_project_arguments( '-Wshadow', '-Wsuggest-attribute=format', '-Wwrite-strings', + '-Wdiscarded-qualifiers', ]), language: 'c' )